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   1 /*
   2  * lookup_table.c
   3  *
   4  * Lookup table, implemented as a hash table, that maps dentries to file
   5  * resources.
   6  */
   7
   8 /*
   9  * Copyright (C) 2012 Eric Biggers
  10  *
  11  * This file is part of wimlib, a library for working with WIM files.
  12  *
  13  * wimlib is free software; you can redistribute it and/or modify it under the
  14  * terms of the GNU General Public License as published by the Free
  15  * Software Foundation; either version 3 of the License, or (at your option)
  16  * any later version.
  17  *
  18  * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
  19  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  20  * A PARTICULAR PURPOSE. See the GNU General Public License for more
  21  * details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with wimlib; if not, see http://www.gnu.org/licenses/.
  25  */
  26
  27 #include "wimlib_internal.h"
  28 #include "lookup_table.h"
  29 #include "io.h"
  30 #include <errno.h>
  31
  32 #ifdef WITH_FUSE
  33 #include <unistd.h>
  34 #endif
  35
  36 struct lookup_table *new_lookup_table(size_t capacity)
  37 {
  38         struct lookup_table *table;
  39         struct hlist_head *array;
  40
  41         table = MALLOC(sizeof(struct lookup_table));
  42         if (!table)
  43                 goto err;
  44         array = CALLOC(capacity, sizeof(array[0]));
  45         if (!array) {
  46                 FREE(table);
  47                 goto err;
  48         }
  49         table->num_entries = 0;
  50         table->capacity = capacity;
  51         table->array = array;
  52         return table;
  53 err:
  54         ERROR("Failed to allocate memory for lookup table with capacity %zu",
  55               capacity);
  56         return NULL;
  57 }
  58
  59 struct lookup_table_entry *new_lookup_table_entry()
  60 {
  61         struct lookup_table_entry *lte;
  62
  63         lte = CALLOC(1, sizeof(struct lookup_table_entry));
  64         if (!lte) {
  65                 ERROR("Out of memory (tried to allocate %zu bytes for "
  66                       "lookup table entry)",
  67                       sizeof(struct lookup_table_entry));
  68                 return NULL;
  69         }
  70
  71         lte->part_number  = 1;
  72         lte->refcnt       = 1;
  73         return lte;
  74 }
  75
  76 void free_lookup_table_entry(struct lookup_table_entry *lte)
  77 {
  78         if (lte) {
  79                 switch (lte->resource_location) {
  80                 case RESOURCE_IN_STAGING_FILE:
  81                 case RESOURCE_IN_ATTACHED_BUFFER:
  82                 case RESOURCE_IN_FILE_ON_DISK:
  83                         wimlib_assert(((void*)&lte->file_on_disk ==
  84                                       (void*)&lte->staging_file_name)
  85                                       && ((void*)&lte->file_on_disk ==
  86                                       (void*)&lte->attached_buffer));
  87                         FREE(lte->file_on_disk);
  88                         break;
  89 #ifdef WITH_NTFS_3G
  90                 case RESOURCE_IN_NTFS_VOLUME:
  91                         if (lte->ntfs_loc) {
  92                                 FREE(lte->ntfs_loc->path_utf8);
  93                                 FREE(lte->ntfs_loc->stream_name_utf16);
  94                                 FREE(lte->ntfs_loc);
  95                         }
  96                         break;
  97 #endif
  98                 default:
  99                         break;
 100                 }
 101                 FREE(lte->extracted_file);
 102                 FREE(lte);
 103         }
 104 }
 105
 106 static int do_free_lookup_table_entry(struct lookup_table_entry *entry,
 107                                       void *ignore)
 108 {
 109         free_lookup_table_entry(entry);
 110         return 0;
 111 }
 112
 113
 114 void free_lookup_table(struct lookup_table *table)
 115 {
 116         DEBUG2("Freeing lookup table");
 117         if (table) {
 118                 if (table->array) {
 119                         for_lookup_table_entry(table,
 120                                                do_free_lookup_table_entry,
 121                                                NULL);
 122                         FREE(table->array);
 123                 }
 124                 FREE(table);
 125         }
 126 }
 127
 128 /*
 129  * Inserts an entry into the lookup table.
 130  *
 131  * @table:      A pointer to the lookup table.
 132  * @entry:      A pointer to the entry to insert.
 133  */
 134 void lookup_table_insert(struct lookup_table *table,
 135                          struct lookup_table_entry *lte)
 136 {
 137         size_t i = lte->hash_short % table->capacity;
 138         hlist_add_head(&lte->hash_list, &table->array[i]);
 139
 140         /* XXX Make the table grow when too many entries have been inserted. */
 141         table->num_entries++;
 142 }
 143
 144 static void finalize_lte(struct lookup_table_entry *lte)
 145 {
 146         #ifdef WITH_FUSE
 147         if (lte->resource_location == RESOURCE_IN_STAGING_FILE) {
 148                 unlink(lte->staging_file_name);
 149                 wimlib_assert(lte->staging_list.next);
 150                 wimlib_assert(lte->staging_list.prev);
 151                 list_del(&lte->staging_list);
 152         }
 153         #endif
 154         free_lookup_table_entry(lte);
 155 }
 156
 157 /* Decrements the reference count for the lookup table entry @lte.  If its
 158  * reference count reaches 0, it is unlinked from the lookup table.  If,
 159  * furthermore, the entry has no opened file descriptors associated with it, the
 160  * entry is freed.  */
 161 struct lookup_table_entry *
 162 lte_decrement_refcnt(struct lookup_table_entry *lte, struct lookup_table *table)
 163 {
 164         wimlib_assert(lte);
 165         wimlib_assert(lte->refcnt);
 166         if (--lte->refcnt == 0) {
 167                 lookup_table_unlink(table, lte);
 168         #ifdef WITH_FUSE
 169                 if (lte->num_opened_fds == 0)
 170         #endif
 171                 {
 172                         finalize_lte(lte);
 173                         lte = NULL;
 174                 }
 175         }
 176         return lte;
 177 }
 178
 179 #ifdef WITH_FUSE
 180 struct lookup_table_entry *
 181 lte_decrement_num_opened_fds(struct lookup_table_entry *lte,
 182                              struct lookup_table *table)
 183 {
 184         if (lte) {
 185                 wimlib_assert(lte->num_opened_fds);
 186                 if (--lte->num_opened_fds == 0 && lte->refcnt == 0) {
 187                         lookup_table_unlink(table, lte);
 188                         finalize_lte(lte);
 189                         lte = NULL;
 190                 }
 191         }
 192         return lte;
 193 }
 194 #endif
 195
 196 /*
 197  * Calls a function on all the entries in the lookup table.  Stop early and
 198  * return nonzero if any call to the function returns nonzero.
 199  */
 200 int for_lookup_table_entry(struct lookup_table *table,
 201                            int (*visitor)(struct lookup_table_entry *, void *),
 202                            void *arg)
 203 {
 204         struct lookup_table_entry *lte;
 205         struct hlist_node *pos, *tmp;
 206         int ret;
 207
 208         for (size_t i = 0; i < table->capacity; i++) {
 209                 hlist_for_each_entry_safe(lte, pos, tmp, &table->array[i],
 210                                           hash_list)
 211                 {
 212                         ret = visitor(lte, arg);
 213                         if (ret != 0)
 214                                 return ret;
 215                 }
 216         }
 217         return 0;
 218 }
 219
 220
 221 /*
 222  * Reads the lookup table from a WIM file.
 223  */
 224 int read_lookup_table(WIMStruct *w)
 225 {
 226         u64    num_entries;
 227         u8     buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 228         int    ret;
 229         struct lookup_table *table;
 230         struct lookup_table_entry *cur_entry = NULL, *duplicate_entry;
 231
 232         DEBUG("Reading lookup table: offset %"PRIu64", size %"PRIu64"",
 233               w->hdr.lookup_table_res_entry.offset,
 234               w->hdr.lookup_table_res_entry.original_size);
 235
 236         if (fseeko(w->fp, w->hdr.lookup_table_res_entry.offset, SEEK_SET) != 0) {
 237                 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read "
 238                                  "lookup table",
 239                                  w->hdr.lookup_table_res_entry.offset);
 240                 return WIMLIB_ERR_READ;
 241         }
 242
 243         num_entries = w->hdr.lookup_table_res_entry.original_size /
 244                       WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE;
 245         table = new_lookup_table(num_entries * 2 + 1);
 246         if (!table)
 247                 return WIMLIB_ERR_NOMEM;
 248
 249         while (num_entries--) {
 250                 const u8 *p;
 251
 252                 if (fread(buf, 1, sizeof(buf), w->fp) != sizeof(buf)) {
 253                         if (feof(w->fp)) {
 254                                 ERROR("Unexpected EOF in WIM lookup table!");
 255                         } else {
 256                                 ERROR_WITH_ERRNO("Error reading WIM lookup "
 257                                                  "table");
 258                         }
 259                         ret = WIMLIB_ERR_READ;
 260                         goto out;
 261                 }
 262                 cur_entry = new_lookup_table_entry();
 263                 if (!cur_entry) {
 264                         ret = WIMLIB_ERR_NOMEM;
 265                         goto out;
 266                 }
 267                 cur_entry->wim = w;
 268                 cur_entry->resource_location = RESOURCE_IN_WIM;
 269
 270                 p = get_resource_entry(buf, &cur_entry->resource_entry);
 271                 p = get_u16(p, &cur_entry->part_number);
 272                 p = get_u32(p, &cur_entry->refcnt);
 273                 p = get_bytes(p, SHA1_HASH_SIZE, cur_entry->hash);
 274
 275                 if (cur_entry->part_number != w->hdr.part_number) {
 276                         ERROR("A lookup table entry in part %hu of the WIM "
 277                               "points to part %hu",
 278                               w->hdr.part_number, cur_entry->part_number);
 279                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 280                         goto out_free_cur_entry;
 281
 282                 }
 283
 284                 if (is_zero_hash(cur_entry->hash)) {
 285                         ERROR("The WIM lookup table contains an entry with a "
 286                               "SHA1 message digest of all 0's");
 287                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 288                         goto out_free_cur_entry;
 289                 }
 290
 291                 duplicate_entry = __lookup_resource(table, cur_entry->hash);
 292                 if (duplicate_entry) {
 293                         ERROR("The WIM lookup table contains two entries with the "
 294                               "same SHA1 message digest!");
 295                         ERROR("The first entry is:");
 296                         print_lookup_table_entry(duplicate_entry);
 297                         ERROR("The second entry is:");
 298                         print_lookup_table_entry(cur_entry);
 299                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 300                         goto out_free_cur_entry;
 301                 }
 302
 303                 if (!(cur_entry->resource_entry.flags & WIM_RESHDR_FLAG_COMPRESSED)
 304                     && (cur_entry->resource_entry.size !=
 305                       cur_entry->resource_entry.original_size))
 306                 {
 307                         ERROR("Found uncompressed resource with original size "
 308                               "not the same as compressed size");
 309                         ERROR("The lookup table entry for the resource is as follows:");
 310                         print_lookup_table_entry(cur_entry);
 311                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 312                         goto out_free_cur_entry;
 313                 }
 314                 lookup_table_insert(table, cur_entry);
 315
 316         }
 317         DEBUG("Done reading lookup table.");
 318         w->lookup_table = table;
 319         return 0;
 320 out_free_cur_entry:
 321         FREE(cur_entry);
 322 out:
 323         free_lookup_table(table);
 324         return ret;
 325 }
 326
 327
 328 /*
 329  * Writes a lookup table entry to the output file.
 330  */
 331 int write_lookup_table_entry(struct lookup_table_entry *lte, void *__out)
 332 {
 333         FILE *out;
 334         u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 335         u8 *p;
 336
 337         out = __out;
 338
 339         /* Don't write entries that have not had file resources or metadata
 340          * resources written for them. */
 341         if (lte->out_refcnt == 0)
 342                 return 0;
 343
 344         if (lte->output_resource_entry.flags & WIM_RESHDR_FLAG_METADATA)
 345                 DEBUG("Writing metadata entry at %lu (orig size = %zu)",
 346                       ftello(out), lte->output_resource_entry.original_size);
 347
 348         p = put_resource_entry(buf, &lte->output_resource_entry);
 349         p = put_u16(p, lte->part_number);
 350         p = put_u32(p, lte->out_refcnt);
 351         p = put_bytes(p, SHA1_HASH_SIZE, lte->hash);
 352         if (fwrite(buf, 1, sizeof(buf), out) != sizeof(buf)) {
 353                 ERROR_WITH_ERRNO("Failed to write lookup table entry");
 354                 return WIMLIB_ERR_WRITE;
 355         }
 356         return 0;
 357 }
 358
 359
 360 int lte_zero_real_refcnt(struct lookup_table_entry *lte, void *ignore)
 361 {
 362         lte->real_refcnt = 0;
 363         return 0;
 364 }
 365
 366 int lte_zero_out_refcnt(struct lookup_table_entry *lte, void *ignore)
 367 {
 368         lte->out_refcnt = 0;
 369         return 0;
 370 }
 371
 372 int lte_free_extracted_file(struct lookup_table_entry *lte, void *ignone)
 373 {
 374         FREE(lte->extracted_file);
 375         lte->extracted_file = NULL;
 376         return 0;
 377 }
 378
 379 void print_lookup_table_entry(const struct lookup_table_entry *lte)
 380 {
 381         if (!lte) {
 382                 putchar('\n');
 383                 return;
 384         }
 385         printf("Offset            = %"PRIu64" bytes\n",
 386                lte->resource_entry.offset);
 387         printf("Size              = %"PRIu64" bytes\n",
 388                (u64)lte->resource_entry.size);
 389         printf("Original size     = %"PRIu64" bytes\n",
 390                lte->resource_entry.original_size);
 391         printf("Part Number       = %hu\n", lte->part_number);
 392         printf("Reference Count   = %u\n", lte->refcnt);
 393         printf("Hash              = 0x");
 394         print_hash(lte->hash);
 395         putchar('\n');
 396         printf("Flags             = ");
 397         u8 flags = lte->resource_entry.flags;
 398         if (flags & WIM_RESHDR_FLAG_COMPRESSED)
 399                 fputs("WIM_RESHDR_FLAG_COMPRESSED, ", stdout);
 400         if (flags & WIM_RESHDR_FLAG_FREE)
 401                 fputs("WIM_RESHDR_FLAG_FREE, ", stdout);
 402         if (flags & WIM_RESHDR_FLAG_METADATA)
 403                 fputs("WIM_RESHDR_FLAG_METADATA, ", stdout);
 404         if (flags & WIM_RESHDR_FLAG_SPANNED)
 405                 fputs("WIM_RESHDR_FLAG_SPANNED, ", stdout);
 406         putchar('\n');
 407         switch (lte->resource_location) {
 408         case RESOURCE_IN_WIM:
 409                 if (lte->wim->filename) {
 410                         printf("WIM file          = `%s'\n",
 411                                lte->wim->filename);
 412                 }
 413                 break;
 414         case RESOURCE_IN_FILE_ON_DISK:
 415                 printf("File on Disk      = `%s'\n", lte->file_on_disk);
 416                 break;
 417         case RESOURCE_IN_STAGING_FILE:
 418                 printf("Staging File      = `%s'\n", lte->staging_file_name);
 419                 break;
 420         default:
 421                 break;
 422         }
 423         putchar('\n');
 424 }
 425
 426 static int do_print_lookup_table_entry(struct lookup_table_entry *lte,
 427                                        void *ignore)
 428 {
 429         print_lookup_table_entry(lte);
 430         return 0;
 431 }
 432
 433 /*
 434  * Prints the lookup table of a WIM file.
 435  */
 436 WIMLIBAPI void wimlib_print_lookup_table(WIMStruct *w)
 437 {
 438         for_lookup_table_entry(w->lookup_table,
 439                                do_print_lookup_table_entry,
 440                                NULL);
 441 }
 442
 443 /*
 444  * Looks up an entry in the lookup table.
 445  */
 446 struct lookup_table_entry *
 447 __lookup_resource(const struct lookup_table *table, const u8 hash[])
 448 {
 449         size_t i;
 450         struct lookup_table_entry *lte;
 451         struct hlist_node *pos;
 452
 453         wimlib_assert(table);
 454
 455         i = *(size_t*)hash % table->capacity;
 456         hlist_for_each_entry(lte, pos, &table->array[i], hash_list)
 457                 if (hashes_equal(hash, lte->hash))
 458                         return lte;
 459         return NULL;
 460 }
 461
 462 #ifdef WITH_FUSE
 463 /*
 464  * Finds the dentry, lookup table entry, and stream index for a WIM file stream,
 465  * given a path name.
 466  *
 467  * This is only for pre-resolved inodes.
 468  */
 469 int lookup_resource(WIMStruct *w, const char *path,
 470                     int lookup_flags,
 471                     struct dentry **dentry_ret,
 472                     struct lookup_table_entry **lte_ret,
 473                     u16 *stream_idx_ret)
 474 {
 475         struct dentry *dentry;
 476         struct lookup_table_entry *lte;
 477         u16 stream_idx;
 478         const char *stream_name = NULL;
 479         struct inode *inode;
 480         char *p = NULL;
 481
 482         if (lookup_flags & LOOKUP_FLAG_ADS_OK) {
 483                 stream_name = path_stream_name(path);
 484                 if (stream_name) {
 485                         p = (char*)stream_name - 1;
 486                         *p = '\0';
 487                 }
 488         }
 489
 490         dentry = get_dentry(w, path);
 491         if (p)
 492                 *p = ':';
 493         if (!dentry)
 494                 return -ENOENT;
 495
 496         inode = dentry->d_inode;
 497
 498         wimlib_assert(inode->resolved);
 499
 500         if (!(lookup_flags & LOOKUP_FLAG_DIRECTORY_OK)
 501               && inode_is_directory(inode))
 502                 return -EISDIR;
 503
 504         if (stream_name) {
 505                 struct ads_entry *ads_entry;
 506                 u16 ads_idx;
 507                 ads_entry = inode_get_ads_entry(inode, stream_name,
 508                                                 &ads_idx);
 509                 if (ads_entry) {
 510                         stream_idx = ads_idx + 1;
 511                         lte = ads_entry->lte;
 512                         goto out;
 513                 } else {
 514                         return -ENOENT;
 515                 }
 516         } else {
 517                 lte = inode->lte;
 518                 stream_idx = 0;
 519         }
 520 out:
 521         if (dentry_ret)
 522                 *dentry_ret = dentry;
 523         if (lte_ret)
 524                 *lte_ret = lte;
 525         if (stream_idx_ret)
 526                 *stream_idx_ret = stream_idx;
 527         return 0;
 528 }
 529 #endif
 530
 531 static void inode_resolve_ltes(struct inode *inode, struct lookup_table *table)
 532 {
 533         struct lookup_table_entry *lte;
 534
 535         /* Resolve the default file stream */
 536         lte = __lookup_resource(table, inode->hash);
 537         inode->lte = lte;
 538         inode->resolved = true;
 539
 540         /* Resolve the alternate data streams */
 541         for (u16 i = 0; i < inode->num_ads; i++) {
 542                 struct ads_entry *cur_entry = &inode->ads_entries[i];
 543                 lte = __lookup_resource(table, cur_entry->hash);
 544                 cur_entry->lte = lte;
 545         }
 546 }
 547
 548 /* Resolve a dentry's lookup table entries
 549  *
 550  * This replaces the SHA1 hash fields (which are used to lookup an entry in the
 551  * lookup table) with pointers directly to the lookup table entries.  A circular
 552  * linked list of streams sharing the same lookup table entry is created.
 553  *
 554  * This function always succeeds; unresolved lookup table entries are given a
 555  * NULL pointer.
 556  */
 557 int dentry_resolve_ltes(struct dentry *dentry, void *table)
 558 {
 559         if (!dentry->d_inode->resolved)
 560                 inode_resolve_ltes(dentry->d_inode, table);
 561         return 0;
 562 }
 563
 564 /* Return the lookup table entry for the unnamed data stream of an inode, or
 565  * NULL if there is none.
 566  *
 567  * You'd think this would be easier than it actually is, since the unnamed data
 568  * stream should be the one referenced from the inode itself.  Alas, if there
 569  * are named data streams, Microsoft's "imagex.exe" program will put the unnamed
 570  * data stream in one of the alternate data streams instead of inside the WIM
 571  * dentry itself.  So we need to check the alternate data streams too.
 572  *
 573  * Also, note that a dentry may appear to have than one unnamed stream, but if
 574  * the SHA1 message digest is all 0's then the corresponding stream does not
 575  * really "count" (this is the case for the inode's own file stream when the
 576  * file stream that should be there is actually in one of the alternate stream
 577  * entries.).  This is despite the fact that we may need to extract such a
 578  * missing entry as an empty file or empty named data stream.
 579  */
 580 struct lookup_table_entry *
 581 inode_unnamed_lte(const struct inode *inode,
 582                    const struct lookup_table *table)
 583 {
 584         if (inode->resolved)
 585                 return inode_unnamed_lte_resolved(inode);
 586         else
 587                 return inode_unnamed_lte_unresolved(inode, table);
 588 }
 589